This invention relates generally to a custom formed leg brace to stabilize an unstable knee during various activities and the process for manufacturing such a brace, and more particularly to a leg brace which is lighter, stronger and more comfortably controls rotation or other tibial movement than prior art braces.
After injury to the leg, and more particularly the knee, it is recommended practice to stabilize the knee and prevent rotation of the leg utilizing a brace as is known from U.S. Pat. No. 4,620,532.
Prior art leg braces essentially come in two forms. The first, completely custom braces, require the making of a plaster cast of a user's leg, the transport of this plaster cast to the factory, and thereafter the fabrication of a leg brace from scratch which is custom fabricated to fit the leg cast. This process is satisfactory, however the procedure is expensive and very time consuming. Alternatively, it is possible to purchase an "off the shelf" brace, which come in a variety of sizes, but are not custom made for the user's leg. This brace is also satisfactory, however, while the user is able to begin use of the leg brace immediately, the fit of the brace may not be precise, and as such the protection needed by the user of this brace may not be provided by this type of brace. Therefore, it would be desirable to provide a brace which was less expensive and had less lead time to produce, such as the "off the shelf" brace, but provided a tailored fit, such as the custom fabricated brace model.
In prior art leg braces, typically a very complicated and heavy strap assembly is used to retain the structural portion of the brace against the knee or leg. Typically, this strap assembly consists of any number of Velcro.RTM. straps riveted to the outside of the structural portion of the brace. Thereafter, these straps are interwound and wrapped about the user's legs in a specific fashion, thereby pushing the brace towards the user's legs from the outside of the brace. This resulted in braces which were very cumbersome and heavy, since each strap requires at least one metal rivet connected to the outside of the structural portion of the brace to retain the straps connected to the brace. Additionally such braces require many parts such as frame pads, hook and loop straps, strap pads, and an under sleeve. Also, the construction of such a brace is time consuming and expensive since each rivet and strap must be individually connected to the brace. Additionally, these external retention mechanisms are not visually pleasing.
Often, prior art leg braces are formed using a thermosetting material and process. This process to form a brace requires complex forming steps including the proper mixing of chemicals at precise temperatures. Furthermore, the by products of thermosetting are noxious fumes and chemical by products which are harmful to the environment or require great care in disposal.
Prior art leg and knee braces have been satisfactory. However, they also suffer from a number of defects.
Both of the prior art leg and knee braces are very heavy. In order to provide sufficient structural integrity to the brace so that it may prevent unwanted movement in the leg or knee, the material used is of a metal or thermoset material which is very heavy, and as a result fatigues the user and limits the movement of the user of the brace because of the weight. Heavier braces tend to migrate down a user's leg, thereby reducing the efficiency of the brace.
Next, the prior art leg and knee braces do not sufficiently protect against rotation of the tibia. Specifically, after a user has suffered an injury which causes any ligimental instability, such as an anterior cruciate ligament (ACL) tear (by way of example), the tibial bone not only has a tendency to move forward (anteriorly), but also rotates (in other situations, the tibia might move in other directions). However, the prior art leg brace which is designed to employ a transverse structural member across the front of the user's leg in order to restrict any anterior tibial movement does not address any of the rotation or other directional movement problems associated with ligament instability. Additionally, since this transverse structural member comes into contact with the tibia at only one point, any force imparted to the brace will be transferred to the point of the tibia in contact with the structural member, thereby causing undue pain for the user, and possibly precluding the user from sufficiently tightening the brace to provide the required support. It would be beneficial to provide a leg brace which is rigid but light, and addresses both the anterior movement and rotational movement of the tibia, while being comfortable for the user.
All braces must be retained tightly against the leg of the user to be effective. Straps on prior art braces do not provide any mechanism to enhance the grip of the strap by the user. It would be beneficial to provide a strap with a grip enhancing feature to assist the user in pulling the brace tightly to a users leg.
Finally, these multiple strap harness systems often require the user to over or underlay the straps in a particular manner so as to insure proper use of the brace. However, one who is not experienced in the use of such a brace may attach the straps improperly, therefore reducing the effectiveness of the brace. Additionally, to properly put on the brace takes a long time for a user. Since the straps are connected to the outside of the brace, and the brace is pushed towards the leg, it may be uncomfortable for the user, and additionally the brace may shift since only the hard structural portion of the brace is being retained against the leg by straps situated on the outside thereof. Adding to the discomfort is the requirement of an underbrace sleeve worn about the user's leg. Therefore, it is desired to provide a leg brace which overcomes the problems of the prior art and does not utilize such a complicated strap system, but rather utilizes a simplified system for retaining the brace against the leg. Additionally, it would be desirable to provide a leg brace where the harness system rather than being riveted to the outside of the brace, was riveted to the inside of the brace so that the brace could be pulled toward the leg, and be more surely retained on the user's leg and the harness would be in contact with the leg rather than the structural portion of the brace, thereby improving the fit and comfort of the brace and precluding the requirement of any underbrace sleeve.